Heat-straightening repairs to a steel road bridge

Abstract

On 16 July 2002 a low-loader lorry carrying heavy machinery travelling eastbound on the A27 struck the underside of Brockhampton Road new bridge. The bridge suffered structural damage to the main beams and bracing. From an initial emergency inspection, the damage was found to be located close to the point of contraflexure in an area where the bottom flange was in tension. It was not considered necessary to impose immediate closures or traffic restrictions. A heat-straightening repair of the damaged beams was proposed. Detailed analysis using both hand calculations and the finite-element method confirmed the structural adequacy of the bridge to undergo the heat-straightening process. These checks encompassed the temporary conditions prior to, during and after the heating. The major heat-straightening process was successfully completed on site in ten days. Impact damage to the beams was repaired within acceptable tolerances and the straightened steel was subjected to hardness and magnetic particle investigation testing. The repairs to Brockhampton Road new bridge were concluded without undue disruption to the travelling public or local residents.